# Returning values from when expressions

**URL:** <https://forums.kodeco.com/t/returning-values-from-when-expressions/82766>\
**Category:** Kotlin Apprentice\
**Created:** [September 24, 2019, 4:16pm UTC](https://forums.kodeco.com/t/returning-values-from-when-expressions/82766 "2019-09-24T16:16:58Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![chuck\_taylor](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/chuck_taylor/32/81494_2.png) [@chuck\_taylor](https://forums.kodeco.com/u/chuck_taylor)\
**Post date:** [September 24, 2019, 4:16pm UTC](https://forums.kodeco.com/t/returning-values-from-when-expressions/82766/1 "2019-09-24T16:16:59Z")

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On page 105 we learn how we can return values from `when` expressions. These when expressions sort of makes me think of a switch statement in other languages, but I am trying to better understand what exactly gets returned.

The example provided is:

```auto
val numberName = when (number) {
  2 -> "two"
  4 -> "four"
  6 -> "six"
  8 -> "eight"
  10 -> "ten"
  else -> {
    println("Unknown number")
"Unknown"
 }
}
println(numberName) // > ten

```

When number for example is `11`, the else block is executed, so we see `Unknown number`, followed by the last println statement which shows the returned value of `Unknown`.

While the first branches simply return a string, I’m curious how this else block works without a ‘return’ keyword or anything. When I try adding the return keyword before `Unknown`, I get an error that it was expecting a type of Unit and found a String. I guess I’m wondering how it knows to execute println() in the else block, but return `Unknown`

Hope that question makes sense. 🙂

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**Author:** ![macsimus](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/macsimus/32/109104_2.png) [@macsimus](https://forums.kodeco.com/u/macsimus)\
**Post date:** [September 26, 2019, 12:18am UTC](https://forums.kodeco.com/t/returning-values-from-when-expressions/82766/2 "2019-09-26T00:18:24Z")

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Thanks for the question @chuck_taylor! In Kotlin, the last expression in a block (denoted by the braces in the `else` case) is returned by the block, in this case the value of “Unknown”. The `println` call just executes normally before the value of “Unknown” is returned. The block itself is inferred to return a `String`, since the `when` expression cases besides the else all return strings.

The same would be true if you were assigning a value using an if-else expression. The if case could have a bunch of statements, and the last expression in the if case would be its return value, without the need for a `return` keyword. Same for the else case.

I hope that helps and thanks again!

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<div class="post-metadata">

**Author:** ![chuck\_taylor](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/chuck_taylor/32/81494_2.png) [@chuck\_taylor](https://forums.kodeco.com/u/chuck_taylor)\
**Post date:** [September 26, 2019, 12:33am UTC](https://forums.kodeco.com/t/returning-values-from-when-expressions/82766/3 "2019-09-26T00:33:34Z")

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That does help. Thank you for taking the time to read my question and reply. Just a bit of syntax to get used to I suppose. I am surprised though that using the return keyword throws an error - surprised I suppose that omitting ‘return’ is not optional.

However, thank you again for clarifying how it works!